SMART ANTENNA SMART ANTENNA SYSTEMSSYSTEMS

GUIDED BY: GUIDED BY: SHEKHAR PATLESHEKHAR PATLE

Submitted By: Kamlesh Nagpure

1. Concept of smart antenna2. Level of Intelligence3. Evolution of smart antenna 4. Element of smart antenna 5. Aim6. Types of smart antenna7. Applications8. Advantages9. Disadvantages10. Conclusions

Contents

The Concept- Smart Antenna consists of a number of radiating

elements, a combining/dividing network and a control unit.

- Control unit can be called the smart antenna’s intelligence. It is realized using a digital signal processor (DSP).

- Based on this definition of smart antenna, one can define “levels of Intelligence”.

Levels of Intelligence1.) Switched lobe (SL)

- simplest technique, also called switched beam. - comprises of only a basic switching function

between separate directive antennas or predefined beams of an array.

- the setting that gives the best performance is chosen.

Levels of Intelligence2.)Dynamically phased array (PA):

- a direction of arrival (DOA) algorithm is included for the signal received from the user.

- continuous tracking can be achieved. - generalization of the switched lobe concept.

Levels of Intelligence3.) Adaptive array (AA):

- a DOA algorithm for determining the direction toward interference sources (e.g., other users) is added.

- the radiation pattern can then be adjusted to null out the interferers.

Levels of Intelligence

Evolution of Smart Antennas An evolution can be foreseen in the utilization of

smart antennas. The evolution can be divided into three phases:

- Smart antennas are used on uplink only. This concept is called high sensitivity receiver (HSR).

- In the second phase, directed antenna beams are used on the downlink direction in addition to HSR.

- The last stage in the development will be full space division multiple access (SDMA).

Smart Antenna Array:• antenna array with a digital signal

processing capability to transmit and receive in an adaptive and spatially sensitive manner.

“Smart” >> digital signal processing facility

Elements of a Smart Antenna

• number of radiating elements

• a combining/dividing network • control unit

Aim :

• to maximize the antenna gain in the desired direction

• to minimize the gain in directions of interferers

Types of Smart Antennas

Switched lobe (SL): ( also called “switched beam” )

• simplest technique

• comprises only a basic switching function between separate directive antennas or predefined beams of an array

Types of Smart Antennas - cont’d

Dynamically phased array (PA):

• continuous tracking can be achieved by including a direction of arrival (DoA) algorithm for the signal received from the user

• can be viewed as a generalization of the switched lobe concept

Conventional Antennas & Arrays

Antenna

Top View

Antenna Array

Top View

Omnidirectional Sectorized

WHY SMART ANTENNA ARRAYS ARE

SUPERIOR TO CONVENTIONAL ANTENNAS

Switched Beam System Adaptive Array

Antenna Array

Desired User

Interfering User

Antenna Array

Active Beam

Interference Rejection Comparison

Desired Signals

Co-channel Interfering Signals

Smart Antennas for Base Stations

• the idea of smart antennas is to use base station antenna patterns that are not fixed, but adapt to the current radio conditions

• can be visualized as the antenna directing a beam toward the communication partner only

SDMA(Space Division Multiple Access)

• more than one user can be allocated to the same physical communications channel simultaneously in the same cell

• separated by angle only

• in a TDMA system, two users will be allocated to the same time slot and carrier frequency at the same time and in the same cell

SDMA (Space Division Multiple Access)

USAGE

Applications to:

• cellular and wireless networks

• radar

• electronic warfare (EWF) as a countermeasure to electronic jamming

• satellite systems

WHY SMART ANTENNA ARRAYS?

Higher Capacity

Higher Coverage

Higher bit rate

Improved link quality

Spectral efficiency

Mobility

Drawbacks and Cost factors- Transceiver Complexity -- A smart antenna

transceiver is much more complex than a traditional base station transceiver.

- Need for more powerful algorithms, processors and control systems.

- Resource Management -- New demands on network functions such as resource and mobility management are needed.

- Physical Size -- For the smart antenna to obtain a reasonable gain, an array antenna with several elements is necessary.

Smart Antennas for Wireless Systems

Conclusions• Smart antennas can improve user experience and

system capacity by reducing interference, extending range, increasing data rates, and improving quality

• Smart antennas can be implemented in the physical layer with little or no impact on standards

• Expertise and experience in the development and deployment of smart antennas for cellular can be applied to develop smart antennas for WLANs, and many other wireless applications

References

www.jackwinters.com/cwc.ppt

www.jackwinters.com/Intel_Smart_Antenna_Workshop.ppt

www.authorstream.com/.../aSGuest41292-355566-smart-antennas-

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